A continuing interest exists in industry for improved gas turbine engines. Gas turbine engines continue to be useful in a wide variety of applications. Operational costs could be substantially improved in many applications by adoption of an improved gas turbine engine that would increase operating efficiency as compared to currently-utilized gas turbine designs. Further, from the point of view of maintenance costs, it would be desirable to develop improved gas turbine engine designs that would reduce the mass of rotating components, since such rotating components are costly when replacement or repair becomes necessary, as compared to non-rotating parts, which although subject to stress and strain from temperature and pressure, are not subject to additional loads due to rotary motion. Thus, it can be appreciated that it would be advantageous to provide a new, high-efficiency gas turbine engine design which minimizes moving parts. Generally, it would be advantageous to provide more horsepower with less weight. And more specifically, it would be advantageous to provide small gas turbines having a relatively high overall efficiency, particularly in the one-half to three megawatt range
A key component of gas turbine engines is the compressor section. Although supersonic compressors have been contemplated for use in gas turbine engines, there remain various technical problems in the field and with respect to which better solutions are required in order to improve operational capability and compression efficiency. In particular, although relatively low pressure ratio supersonic compressors have been proposed for gas turbine engines, there still remains a need for compressors for gas turbine engines that can be easily started, yet be operated at high compression ratios. Further, it would be advantageous to avoid configurations that present moving shocks, such as between moving blades, between moving and fixed blades, or between moving and fixed walls, in order to more simply achieve stability for a normal shock at a selected location in the compressor section of a gas turbine engine.
In short, there remains a need to provide a design for a gas turbine engine with a high pressure ratio supersonic compressor that simultaneously resolves various practical problems, including (a) providing for starting of a compressor designed for high pressure ratio operation, so as to enable control of a normal shock at an effective location in a supersonic diffuser when configured as a stator and designed for high pressure ratio and efficient compression, (b) avoiding excessive numbers of leading edge structures (such as may be encountered in prior art multi-bladed stators), and minimizing other losses encountered by a high velocity supersonic gas stream upon entering a stator, and (c) providing for effective boundary layer control, especially as related to retention of a normal shock at a desirable location, in order to achieve high compression ratios in an efficient manner.